BACTERIAL VECTORS IN DINOFLAGELLATE CIGUATOXIN PRODUCTION
Authors: Jasmine Seda Miro and Nadathur S. Govind
Abstract: Microalgae, such as dinoflagellates, contribute significantly to the production of biomass and organic compounds in the ocean. They are also well-known for their harmful blooms forming the familiar red and brown tide phenomena. Some species are recognized for their ability to produce toxic secondary metabolites capable of passing through the food chain from fish to humans and have been implicated in ciguatera poisoning. Associated bacterial flora have been implicated in the modulation of dinoflagellate growth and toxin production, but this interaction is not well understood. One of the major difficulties in identifying these bacteria responsible is due to a lack of methods for the identification of persistent bacterial associations in the ocean. Additionally, most bacteria are viable but not culturable (VBNC), making the task even more daunting. A persistent association can be defined as a bacterial species that is always found associated with a particular species of alga both in different geographical regions and through time (e.g. symbiosis). Utilizing this premise as a starting point one can now analyze bacterial flora associated with toxic dinoflagellates utilizing culture independent techniques in different areas as well as during different time periods to identify such bacterial vectors that can modulate toxin production. This commentary will evaluate this approach utilizing the dinoflagellate Ostreopsis lenticularis, a tropical benthic dinflagellate (known to produce Ciguatoxin) as an example. The strategy presented here can be used as a general method for the identification of persistent associations not only in phytoplankton but also invertebrates in the ocean that are known to produce biomedically important natural products.